CNN cites source, who they say had read the translated transcript of the audio recording from the Saudi consulate in Istanbul where journalist Jamal Khashoggi was killed by a hit squad on October 2.

In this Jan. 29, 2011 file photo, Saudi journalist Jamal Khashoggi speaks on his cellphone at the World Economic Forum in Davos, Switzerland.
(AP)

"I can't breathe" were the final words of Washington Post columnist Jamal Khashoggi,who was killed at the hands of Saudi agents in Riyadh's Istanbul consulate, according to a CNN report published on Sunday.

The American news network reported that an unnamed source, who had read the complete translated transcript of the audio recording that reportedly captured Khashoggi's last moments, told them that the Saudi journalist could clearly be heard “struggling against a group of people determined to kill him.”

"I can't breathe. I can't breathe,” Khashoggi is heard repeating in the audio, according to the source.

The information provided by the source was verified by the office of one US senator, who has received a briefing on the investigation on Khashoggi’s murder by CIA Director Gina Haspel.

The transcript was "consistent" with that briefing, the senator's office told CNN.

According to the source, Khashoggi immediately recognised one individual as soon as he entered the Saudi consulate in Istanbul on October 2, upon which he asked the man - identified as former Saudi diplomat and intelligence official Maher Abdulaziz Mutreb - what he is doing there.

"You are coming back," Mutreb tells Khashoggi.

"You can't do that," Khashoggi replies, adding that he had people waiting outside for him, apparently referring to his Turkish fiancee Hatice Cengiz who accompanied him to the entrance of the building.

At that point, a group is heard attacking Khashoggi, who is left gasping for air, as he cries: "I can't breathe."

Among several other voices heard in the recording, one belongs to Dr. Salah Muhammad al Tubaiqi, the head of forensic medicine at Saudi Arabia's Interior Ministry, the source told CNN.

Following a series of screams, sawing and cutting can be heard. Tubaiqi then advises others in the room to block out the noise.

"Put your earphones in, or listen to music like me," Tubaiqi says.

It is not certain at what point Khashoggi died.

While the murder takes place, Mutreb makes at least three phone calls. "Tell yours, the thing is done, it's done," he says.

The source said the word "yours" uttered by Mutreb refers to a “superior, or boss.”

Among those updated over the phone by Mutreb, one is believed to be Saud al Qahtani, Crown Prince Mohammed bin Salman's closest aide, the source said.

Responding to a CNN request for a comment on the transcript, a Saudi official told the network that in the version of the transcript and audio recording provided to them by Turkish security channels, there is no “reference or indication of a call being made."

"If there is additional information Turkish authorities have that we are unaware of, we would welcome it being officially handed over to us for review, which we have requested numerous times and are still requesting. And, up until now; we have not received anything," the Saudi official said.